Mesothelioma lung cancer is usually associated with asbestos exposure. In fact there are many other risk factors that cause mesothelioma cancer. One of them is the erionite. Erionite is a naturally occurring fibrous mineral that belongs to a group of minerals called zeolites. Zeolites are hydrated aluminosilicates of the alkaline and alkaline-earth metals.

Erionite was used in the past as a noble metal-impregnated catalyst in a hydrocarbon-cracking process. It was studied for use in fertilizers and to control odors in livestock production, because of its ability to selectively adsorb molecules from air or liquids. In many countries erionite blocks were used (and may be are still used) as building material or in stucco pastes and whitewash.

Erionite was mentioned for the first time as a mesothelioma lung cancer risk factor in 1975, when Turkish government presented a study that uncovered a high incidence of a rare malignant mesothelioma in lung tissues of people in certain small villages in the Cappadocia area in Turkey's central mountainous region. In two small villages the mesothelioma lung cancer accounted for 43% of the deaths during 23 years period of study. Erionite fibers were found in biopsies of lungs of the mesothelioma cancer afflicted people. Comparing this to a 9.7% rate of death from this disease among asbestos insulation installers shows how anomalous this condition was.

Further studies showed erionite causes similar diseases in laboratory animals. When researchers at Mt. Sinai Hospital injected rats with the same dosage of erionite that they used for asbestos, the rats didn't live long enough to get mesothelioma cancer. At a much-reduced dose, the rats did get cancer. Erionite is probably the most toxic known mineral - a milligram of fibers in the lungs is lethal.

Today erionite is considered so hazardous that the EPA requires any one who intends to manufacture, import or process any article containing erionite to notify the E.P.A. 90 days in advance. This gives the EPA a chance to review, limit or prohibit that activity.

Erionite is no longer mined or marketed for commercial purposes.
Although other natural zeolites have many commercial uses (pet litter, soil conditioners, animal feed, waste-water treatment, gas absorbents, etc.) So potential occupational exposure to erionite occurs during the production and
mining of other zeolites.

And there are questions:

Are there other mineralogical hazards like erionite and asbestos?

Should we expected mesothelioma lung cancer increases not only from asbestos exposure after another 20 - 30 years?